Disable Rubocop self assign check in order state machine

Cherry Picked from bc3944d

Co-Authored-By: Elia Schito <[email protected]>

core/lib/spree/core/state_machines/order.rb

@@ -46,7 +46,11 @@ def define_state_machine!
 
               # Persist the state on the order
               after_transition do |order, transition|
-                order.state = order.state
+                # Hard to say if this is really necessary, it was introduced in this commit:
+                # https://github.com/mamhoff/solidus/commit/fa1d66c42e4c04ee7cd1c20d87e4cdb74a226d3d
+                # But it seems to be harmless, so we'll keep it for now.
+                order.state = order.state # rubocop:disable Lint/SelfAssignment
+
                 order.state_changes.create(
                   previous_state: transition.from,
                   next_state:     transition.to,